Method
5 min read
Why we tear off instead of roofing over
A second layer hides the deck, doubles the weight, and shortens the life of the covering above it. Here is what we find underneath, every time.
Written by
Marcus Rhee
Roofing over is a decision to stop looking
Layering new shingles over old ones is legal in most of Oregon and it is almost always the wrong call. The moment you cover the existing surface you give up the only chance you get to inspect the deck, the flashing, and the ventilation. Those three things cause the failures we are called out for. The shingle is rarely the villain.
There is also a physics problem. A second layer traps heat against the new covering and shortens its service life, and it doubles the dead load on a structure that was engineered for one. On a 1920s Portland roof with 1x6 skip sheathing, that matters.
What we find underneath
On the last thirty tear-offs we completed, twenty-six had at least one area of compromised sheathing and nineteen had valley flashing that had been patched rather than replaced. None of that is visible from a ladder, and none of it gets fixed by a roof-over. We would rather hand you photographs of the deck than a lower number.
Next step
Reading is free. So is the walk‑through.
If something here describes your house, book a visit and we will document what is actually happening before quoting a number.